Video Thumbnails – Scan Past Posts (mass update) not working

Love the concept of this plugin, however, it appears to be behaving poorly for me.

• I am using WP 3.5.1.
• I am using a ThemeTrust template
• I installed your Video Thumbnail plugin
• I configured your plugin to Save Local Copy and Auto Set Thumbnails engaged
• I have 80 posts in which the content is a Vimeo IFRAME statement

ISSUE #1:
I wanted to refresh each thumbnail for all of my posts. I first tried using the Scan Past Posts feature (Settings > Video Thumbnails > Scan Past Posts). While each post reported a successful status, and the Posts reflect the correct thumbnail fetched from Vimeo, the media library does not have any images from this feature. The only way it works for me is to edit one post at a time, click Remove Featured Image, then click Reset Video Thumbnail, then click UPDATE. If I don’t do it in that order, the thumbnail will not be in the media library nor associated with the video itself.

ISSUE #2:
Each run of the “Reset Video Thumbnail” produces another copy in the media library, instead of replacing the prior media-ID already associated to the particular post. Moreover, the original and duplicate media thumbnail both show as linked to the post, making it difficult to clean up the library.

Thanks for any assistance you can lend.